#include <iostream>
#include <string>
#include <algorithm>
using namespace std;

//int main()
//{
//	string s;
//	cin >> s;
//	string t = s;
//	reverse(t.begin(), t.end());
//	if(t == s)
//		cout << "yes" << endl;
//	else
//		cout << "no" << endl;
//	return 0;
//}

int main()
{
	string s;
	cin >> s;
	int left = 0;
	int right = s.size() - 1;
	while(left < right)
	{
		if(s[left] == s[right])
		{
			left++;
			right--;
		}
		else
		{
			cout << "no" << endl;
			return 0;
		}
	}
	cout << "yes" << endl;
	return 0;
}
